People have told and retold John Colter’s adventures with embellishments that turn him into a legendary figure like Pecos Bill and Paul Bunyon. But Colter really did cross the plains naked after outrunning hundreds of Blackfeet warriors who were screaming for his scalp. He really was the first white man to visit what is now Yellowstone Park. And his reports of a stinking place where springs spout steam and boiling water were greeted as fantasy and labeled “Colter’s Hell.”